Check if a language can be enabled
Usage:
check_language(<lang>)
where <lang> is a language that may be passed to enable_language() such as Fortran. If CMAKE_<LANG>_COMPILER is already defined the check does nothing. Otherwise it tries enabling the language in a test project. The result is cached in CMAKE_<LANG>_COMPILER as the compiler that was found, or NOTFOUND if the language cannot be enabled. For CUDA which can have an explicit host compiler, the cache CMAKE_CUDA_HOST_COMPILER variable will be set if it was required for compilation.
Example:
check_language(Fortran)
if(CMAKE_Fortran_COMPILER)
enable_language(Fortran)
else()
message(STATUS "No Fortran support")
endif()